Differential modulation of B7-1 and B7-2 isoform expression on human monocytes by cytokines which influence the development of T helper cell phenotype

The co-stimulatory molecules B7-1/B7-2 expressed on the surface of antigen-presenting cells have been suggested to influence the development of T helper 1 (Th1)-versus Th2-immune responses. These studies were conducted to elucidate the effect of immunoregulatory cytokines which influence the development of Th1/Th2 immune responses on the expression of the B7 isoforms B7-1 and B7-2 on resting and activated human monocytes and B cells. Interleukin (IL)-4 and IL-10, which induce the development of Th2 immune responses, down-regulated B7-2 and moderately up-regulated B7-1 expression on resting CD14+ monocytes in peripheral blood mononuclear cells. Interferon-gamma (IFN-gamma), which induces the development of Th1 immune responses, enhanced the expression of both B7-1 and B7-2 isoforms. Tumor necrosis factor (TNF)-alpha, which elicits both Th1- and Th2 characteristics depending on experimental conditions, down-regulated B7-2 but did not alter B7-1 expression. The effect of TNF-alpha and B7-2 expression is not mediated through endogenously produced IL-10, as addition of anti-IL-10 antibodies did not restore B7-2 expression. None of the other cytokines tested, including IL-1 alpha, IL-1 beta, IL-2, IL-5, IL-6, IL-12, granulocyte/macrophage colony-stimulating factor (GM-CSF), and transforming growth factor (TGF)-alpha, modulated the expression of B7 isoforms on resting monocytes. Lipoolysaccharide stimulation of monocytes down-regulated B7-2 and up-regulated B7-1 expression in a manner similar to IL-10. The expression of B7-1 and B7-2 on purified B cells were not altered by any of the cytokines tested, including IL-1 alpha, IL-1 beta, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IFN-gamma, TNF-alpha, TGF-alpha and GM-CSF. Taken together, our results suggest that the cytokines which induce Th1/Th2 immune responses exert differential effects on B7 isoform expression on resting monocytes but have no effect on resting or activated B cells.     

Indoor air quality risk factors for severe lower respiratory tract infections in Inuit infants in Baffin Region, Nunavut: a pilot study

Inuit infants have extremely high rates of lower respiratory tract infection (LRTI), but the causes for this are unclear. The aims of this study were to assess, in young Inuit children in Baffin Region, Nunavut, the feasibility of an epidemiologic study of the association between indoor air quality (IAQ) and respiratory health; to obtain data on IAQ in their housing; and to identify and classify risk factors for LRTI. Twenty houses in Cape Dorset, Nunavut with children below 2 years of age, were evaluated using a structured housing inspection and measurement of IAQ parameters, and a respiratory health questionnaire was administered. Twenty-five percent of the children had, at some time, been hospitalized for chest illness. Houses were very small, and had a median of six occupants per house. Forty-one percent of the houses had a calculated natural air change rate <0.35 air changes per hour. NO(2) concentrations were within the acceptable range. Smokers were present in at least 90% of the households, and nicotine concentrations exceeded 1.5 microg/m(3) in 25% of the dwellings. Particulates were found to be correlated closely with nicotine but not with NO(2) concentrations, suggesting that their main source was cigarette smoking rather than leakage from furnaces. Mattress fungal levels were markedly increased, although building fungal concentrations were low. Dust-mites were virtually non-existent. Potential risk factors related to IAQ for viral LRTI in Inuit infants were observed in this study, including reduced air exchange and environmental tobacco smoke exposure. Severe lower respiratory tract infection is common in Inuit infants. We found reduced air change rates and high occupancy levels in houses in Cape Dorset, which may increase the risk of respiratory infections. This suggests the measures to promote better ventilation or more housing may be beneficial. Further health benefits may be obtained by reducing bed sharing by infants and greater turnover of mattresses, which were found to have high levels of fungi.     

Electrical Characteristics of Chronically Implanted Platinum-Irdium Electrodes

The electrical characteristics of platinum 30 percent-iridium microelectrodes implanted in the cruciate gyrus of cats were monitored during pulsing with charge-balanced, symmetric, cathodicfirst, controlled-current pulse pairs. The amplitude of the pulses spanned the range shown in other studies to be effective as neuronal stimuli, but not to induce histologic or physiologic damage in brain tissue adjacent to the microelectrode tips (10-80 ?, A). Two inflections on the cathodic and anodic charging transients induced by the controlled-current pulses were identified as being due to evolution of molecular hydrogen and the adsorption of oxygen, respectively. Despite the pH dependence of the equilibrium potential of these faradaic reactions, the electrode potentials at the inflections were shown to be independent of stimulus current over most of the useful range of stimulus intensities (20-80/?A, 200-800 ?IC/cm2, and 1-4 A/cm2). Hence, these inflections are valid markers of the true electrode potential, independent of accurate computation of access impedance or a stable reference electrode potential. The implications for monitoring the performance of chronically implanted microelectrodes and for the selection of stimulus parameters is discussed.     

Industrial cybersecurity for a power system and SCADA networks - Be secure

This article presented an overview of the security vulnerabilities of today's industrial control networks. These vulnerabilities exist despite abundant information, standards, and recommended practices published by such organizations as the IEC, IEEE, and ISA. While a good understanding of the issues is required to appreciate the problem, the good news is that it does not take long for the plant engineering forces to get up to speed on the network issues surrounding cybersecurity. Unfortunately, the same can be said for the hacker. Many incidents have occurred and even more are yet to come. Existing systems are vulnerable but can be secured. Given the resources available, future systems can be made secure from the start. Assessing the existing network is straightforward. Producing a human assessment, device inventory, and network diagram is the first step. The development of sensitive assessment tools that can gather the required information, but not affect the- process computers, is also required. All information is gathered, entered into a database, analyzed, and then compared to industry best practices.